It is to be understood that the present invention relates to generators as well as to motors, however, to simplify the description that follows a motor will be described with the understanding that the invention also relates to generators. With this understanding, a synchronous reluctance motor is a synchronous machine that has a stator with poly-phase windings forming a plurality of poles which are similar to those of induction motors. The synchronous reluctance motor also includes a rotor that does not use windings or permanent magnets but does have the same number of poles as the stator. By providing a rotating field in the stator windings, a magnetomotive force acts upon the rotor resulting in the rotor being driven at a synchronous speed proportional to the rotating field in the stator.
The rotor synchronous reluctance generally includes a plurality of rotor sections formed of alternating magnetic and non-magnetic laminations secured to a unitary core. The core has a central axial bore for receiving a shaft. The laminations are inserted between radially extending arms of the core which are formed with a smooth, arcuate recess therebetween. The laminations are secured in the recesses by means of radial fasteners that secure radially-opposing rotor sections to the core. The rotor sections are also secured together by end caps and axial fasteners. The end caps are cup-shaped members with an axially extending outer rim that is disposed about the outermost periphery of the laminations. The axial fasteners extend through the end caps and core to secure the end caps to the rotor. The rotor laminations may also be bonded to one with another and to the core using an epoxy or other adhesive material. A full description of such a synchronous reluctance rotor is disclosed in U.S. Pat. No. 5,296,773 also assigned to the assignee of the present invention.
It is a common method of forming the rotor sections by winding a complete coil of the rotor about a mandrel and cutting the coil in any desired number of sections to form the rotor poles of a reluctance motor. The lamination is simply wound to the desired thickness of the rotor sections. Each segment of the rotor, therefore, is a single large piece of steel laminations having a thickness that is not magnetically related to the stator tooth thickness. This technique results in an un-optimized machine having an airgap pulsating flux component which generates high losses in the rotor.